Dynamo-electricity: its generation, application, transmission, storage and measurement (1884)
Prescott, George B. (George Bartlett), 1830-1894 · New York, D. Appleton · leaf 180
by some of our physicists. Thevacuum is so nearly perfect that none of the tests to which thelamps have been subjected so far indicate the presence of theslightest trace of air. For making his Sprengel pumps and other vacuum apparatus,Mr. Edison fortunately secured the services of an expert… … F!g. So. to afford a light equivalent to a single four feet gas jet, it couldbe forced to give a light equal to that of 8 or 10 such jets. One of the most remarkable experiments connected with theexhibition of these lamps was that of connecting one of themwith the main electrodes by means of a yard…
Electrical engineering
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